The president, on a swing through the Midwest, says the strict new measure threatens Americans’ ‘core values’ and could inflame the debate. He says his administration is considering how to respond.

Reporting aboard Air Force One — President Obama on Wednesday dismissed Arizona's tough new anti-immigration law as a "shortcut" that will merely inflame the debate "instead of solving the problem."

In an impromptu session with reporters at the back of his plane, Obama described the law as a product of "people's frustrations about the border."

Although the president sympathized in part, saying we now have "hundreds of thousands of people coming in" who are "not playing by the rules," he said Arizona had chosen the wrong approach.

The law, signed last week by Republican Gov. Jan Brewer, makes it a state crime to be in Arizona illegally and requires police to check suspects for immigration paperwork. It also bars people from soliciting work or hiring day laborers off the street, and empowers citizens to sue to force authorities to enforce the law.

"What I think is a mistake is when we start having local law enforcement officials empowered to stop people on the suspicion that they may be undocumented workers, because that carries a great amount of risk that core values that we all care about are breached," the president said.

Asked whether his administration might try to mitigate the Arizona law in some way, Obama said: "We're examining it now."

On Tuesday, Atty. Gen. Eric H. Holder Jr. called the law "unfortunate" and said he was considering a court challenge.

Obama made the comments as he was returning from a two-day swing through three Midwestern states — Iowa, Illinois and Missouri — where he sought to defend his policies and promote Democratic candidates in November's midterm elections.

Fixing the fractured immigration system will require a comprehensive solution that may not be possible this year, Obama said.

"l know we've gone through a very tough year and I've been working Congress pretty hard," he told reporters. "So I know there may not be an appetite immediately to dive into another controversial issue. There's still work that has to be done on energy.

"I don't want us to do something just for the sake of politics that doesn't solve the problem. I want us to get together, get the best ideas on both sides, work this through. And when it's ready to go, let's move. But I think we need to start a process at least to open up a smarter, better discussion than the one that is raging" now.

Meanwhile, in Washington, Democratic senators were circulating details about their emerging proposal that would secure the border before illegal immigrants could become legal U.S. residents, the Associated Press reported.

The plan would increase the number of border and immigration enforcement agents and set security benchmarks. The Associated Press obtained a copy of the draft legislation that is being developed by Democratic Sens. Harry Reid of Nevada, Charles E. Schumer of New York and Robert Menendez of New Jersey.

Obama's Midwestern trip was a chance for him to present a folksier face to the public. In recent months, he has been absorbed in arms control treaties and healthcare deals, exposing him to criticism that he is out of touch with the financial worries of everyday Americans.

So he took pains to show a softer side. On Tuesday in Iowa, he proclaimed his love for pie. On Wednesday, he donned a white hardhat in Macon, Mo., while touring a biofuel plant. Later, he ordered a cheeseburger (with lettuce, tomato and mustard) and fries to go during an impromptu stop at Peggy Sue's Cafe in Monroe City, Mo.

Asked what it felt like to take his order, a waitress said: "I take orders every day. He ordered like a normal person."

Then it was on to a 1,000-acre farm owned by Lowell Schachtsiek, where a three-legged dog named Sprinkles greeted the president. The two men toured the property and were overheard discussing oil prices, cattle and the Bible.

"It's a good thing you're reading the Scriptures," Obama said at one point.

The trip comes as Obama is working in partnership with the Democratic National Committee to boost turnout for the midterm elections. Party leaders fear that energized conservative Republicans will flock to the polls while disenchanted liberal Democrats stay home.